The present invention relates to a sputtering apparatus for forming a thin film in semiconductor process techniques or surface treatment techniques.
There have been proposed these kinds of high-speed sputtering apparatuses.
FIG. 4 shows the construction of one of the apparatuses. Reference numeral 1 denotes a vacuum chamber, 2 a target arranged in the chamber 1, 3 a magnetic field parallel to the target 2, 4 permanent magnets for generating the magnetic field 3, 5 a substrate holder arranged to oppose to the target 2, 6 an electric field perpendicularly to the magnetic field 3, 7 a power supply for generating the electric field 6, 8 a gas introducing into the chamber 1 for generating a plasma, 9 a substrate fixedly held on the holder 5, and 10 a yoke constituting a magnetic circuit of the permanent magnets 4.
According to the construction of the apparatus, the magnetic field 4 parallel to the surface of the target 2 is made near the surface of the target 2 by the permanent magnet 4. Between the target 2 and the substrate 5, the electric field 6 perpendicularly to the magnetic field 3 is made by the supply 7. By the magnetic field 3 and the electric field 6, electrons in a discharge region are caught by a space charge so as to perform magnetron discharge through the gas 8. The increase of plasma density near the target 2 by the permanent magnets 4 causes higher sputter rate, thus forming a thin film at high speed.
In the construction of the apparatus, however, an unusual magnetic gap is utilized by using leakage magnetic field as the construction of magnets, thus making the weak and non-uniform magnetic field 3. Therefore, the sputtering is performed at insufficient sputter rate and a part of the target 2 is greatly consumed, thus forming non-uniform stacked films.